changing picture through drop down box

i have a page with a picture in the center.
i need to have a drop down box with 4 options. when i click on a button 'show' the picture changes according to the option chosen. please help!!!!

create a function called via onClick (in the show button) that changes the picture. The adress of the pictures should be contained in the "value" of every element of the list; that is:

<form name="Selects">

<select name="Plants" size="1">
<option value="img/rose.gif">rose</option>
<option value="img/tree.jpg">tree</option>
</select>

and
...
onClick="changefn(originalimg, document.Selects.Plants[document.Selects.Plants.selectedIndex].value)

Hope it works

Here you go:
http://www.wsabstract.com/script/cut173.shtml

Spookster